JP2002322809A - Plastic composite panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel plastic form panel substitutable for woody plywood satisfying rigidity and lightness necessary for a concrete form panel or the like, excellent in nailing property and surface smoothness and also in economical property, and substitutable for woody plywood by using waste plastics, particularly, waste plastics discharged from general homes waste plastics such as waste plastics of the object of the Containers and Packaging Recycling Law as the raw material. SOLUTION: In this plastic composite panel comprising a central layer and outer layers on both sides of the central layers, the central layer and outer layers contain a plastic mixture with a specific gravity of 1.0 or less separated from the waste plastics as raw material, the bubbling ratio of the central layer is 20-60%, fine particles with particle diameter of 0.01-50 μm are dispersively contained in the outer layers, and the central layer is welded and adhered to the outer layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic composite panel used for interior / exterior materials used in the field of construction materials, reinforced concrete construction sites for civil engineering work, concrete formwork panels used in factories, and the like. And a plastic composite panel having excellent bending rigidity.

[0002]

2. Description of the Related Art Inexpensive and highly workable Nanyo plywood has been widely used for concrete formwork panels. However, in recent years, the decline in carbon dioxide consumption due to depletion of forest resources due to overfishing and the emission of carbon dioxide due to incineration after use have been regarded as problems, and the prevention of global warming has become a major issue worldwide. There is a strong demand for the development and spread of alternative materials.

[0003] In response to such demands, many alternative materials have been proposed. For example, metal formwork made of steel or aluminum has excellent rigidity and impact resistance, and is partially used in special fields where these properties are required. It has not become a material.

Promising in terms of lightness, plastics are the main raw material. For example, Japanese Patent Application Laid-Open No. 8-1005
No. 23 discloses a concrete formwork in which a styrofoam plate is integrated as a sandwich structure sandwiched between other thermoplastic resins. Also, JP-A-8-20
No. 7190 discloses a plastic composite panel in which a rigid urethane foam is integrated as a sandwich structure sandwiched between glass fiber-containing polypropylene resin sheets.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-124947 discloses a technique in which a molded product made of waste plastic is used as a panel for a mold.

[0006]

However, the above-mentioned alternative plastic materials do not satisfy the required performance required for concrete formwork panels, and have not been widely used.

For example, Japanese Unexamined Patent Publication No. Hei 8-100523 discloses a concrete form in which the density of a styrene foam plate in the center layer is 1 to 10 kg / m ^3, and this is actually used as a concrete form panel. When used, it is necessary to drive a nail, and there is a problem that the nail is loosened when the pier is hit or the board is easily broken. Also,
When a plastic composite panel whose outer layer is made of resin containing glass fiber disclosed in Japanese Patent Application Laid-Open No. 8-207190 is used as a concrete form, the problem of cracking at the time of nailing and the consumption of the saw blade at the time of saw cutting are quick. In addition, there is a problem in use such as the above, and there is also a problem that recycling after use is difficult.

In a system having a center layer and an outer layer as described above, the center layer being in a foamed state for weight reduction, and a high-rigidity outer layer provided on both surfaces, the adhesion between the center layer and the outer layer is reduced. It is difficult to secure it, and when using an expensive adhesive or the like, it is difficult to substitute wood plywood in terms of economy.

In the prior art, virgin plastic is mostly used for the outer layer in order to increase rigidity. There is also a mold made from waste plastic as in the technique described in JP-A-7-124947, but the pretreatment for obtaining a highly rigid thermosetting resin is complicated, and recycling after use is difficult, and There is a problem that it is difficult to achieve weight reduction. Even in a technique using a recycled resin other than Japanese Patent Application Laid-Open No. 7-124947, a resin having relatively constant components and properties and a small amount of impurities is used, and in most cases, industrial waste that is easy to recycle is used.

Material recycling of waste plastics discharged from general households, for example, waste plastics that must be separated and collected under the Containers and Packaging Recycling Law into formwork panels and the like is extremely significant from the viewpoint of environmental problems. These waste plastics have unstable components and properties, and also contain impurities such as metals and papers other than plastics.Therefore, form panels made from these materials have not been realized. is there.

As described above, the plastic formwork panel is not only inadequate in performance, but also in terms of price, can be used as a substitute for the timber formwork by competing with the existing plywood formwork. Not. In particular, formwork panels made from waste plastics discharged as general waste are very promising technologies from the viewpoint of global environmental protection, but no promising technologies have been proposed so far.

The present invention provides a novel plastic mold which can satisfy the required rigidity and lightness, is excellent in nailing properties, surface smoothness, and is economical, and can truly replace wood plywood. It is an object of the present invention to provide a frame panel as a raw material from waste plastic, particularly waste plastic discharged from ordinary households, such as waste plastic covered by the Containers and Packaging Recycling Law.

[0013]

In order to solve the above problems, the present invention uses the following means.

(1) In a plastic composite panel having a center layer and outer layers on both sides of the center layer, specific gravity of the center layer and the outer layer separated from used plastics is as follows.
0 or less as a raw material, the center layer has a bubble generation ratio of 20 to 60%, and the outer layer contains fine particles having a particle size of 0.01 μm to 50 μm in a dispersed state. A plastic composite panel wherein the outer layer is melt-bonded.

(2) The plastic composite panel according to (1), wherein the fine particles have a plate shape, and each particle has a major axis of 0.01 μm to 50 μm.

(3) The plastic composite panel according to (1) or (2), wherein the main component of the fine particles is talc.

(4) The plastic composite panel according to any one of (1) to (3), wherein the plastic composite panel contains crushed wood.

[0018]

Embodiments of the present invention will be described below in detail.

FIG. 1 is a schematic sectional view showing one embodiment of the plastic composite panel of the present invention. In FIG.
The plastic composite panel of the present invention comprises a center layer 1 and outer layers 2 on both sides of the center layer, and the center layer 1 has a foamed structure to realize a light weight required for a panel for a concrete formwork or the like. Further, by providing outer layers 2 on both sides of the center layer 1, necessary rigidity is given to the concrete formwork panel.
Since the center layer 1 and the outer layer 2 contain used plastics as raw materials, their components are similar and have excellent compatibility.
It is compatible with each other at the interface and can be melt-bonded. Thus, the center layer 1 and the outer layer 2 are firmly bonded without using an adhesive.

The thickness of the entire plastic composite panel is usually 12 mm or more, which is larger than that of a general plastic panel, and the thickness of the outer layer 2 is 2 to the thickness of the entire panel.
It is preferably about 20%. For example, the whole panel is 1
When the thickness is set to 2 mm, the thickness of the outer layer 2 is set to about 0.5 to 2 mm, more preferably 0.8 to 1.5 mm, so that the outer layer 2 is configured to have both weight reduction and bending rigidity. In the present invention, the outer layer of the plastic composite panel has a particle diameter of 0.01 μm or more.
The rigidity of the panel can be improved by uniformly dispersing the fine particles of 10 μm.

The plastics constituting the central layer and the outer layer in the present invention are intended for both plastic discharged as industrial waste and waste plastic discharged as general household waste. It is preferable to use waste plastics, for example, plastic products covered by the Containers and Packaging Recycling Law. The plastics covered by the Containers and Packaging Recycling Law mainly consist of a mixture of general-purpose plastics such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate, and foreign substances such as metal foil, paper, and other seasonings. However, in order to maintain the lightness of the formwork, or to exclude chlorine-based plastics such as polyvinyl chloride for recycling after use, for example, only low-specific-gravity components are obtained by a process such as specific gravity separation after crushing. Are preferably used separately.
Since water is generally used as a solvent for specific gravity separation, it is industrially easy to separate components having a specific gravity of 1.0 or less.

The separated components having a specific gravity of 1.0 or less are mainly polyethylene and polypropylene, and usually have a form in which some polystyrene and other foreign substances that cannot be separated are mixed. In the present invention, there is no problem even if a low specific gravity component containing some foreign matter is used.

The bubble generation rate of the center layer 1 of the plastic composite panel of the present invention is set to 20 to 60%. In the present invention,
From the viewpoint of improving workability as a mold, it is necessary for the center layer 1 to have a foamed structure having bubbles 3 for weight reduction. However, simply foaming uniformly causes workability as a mold. For example, there may be problems such as a decrease in nail pulling resistance at the time of nailing, nail pull-out, cracking, and the like, and the bending rigidity required as a mold may be insufficient. It is necessary to adjust the conversion to 20 to 60%. From the viewpoint of lightness, it is preferable to use a high foaming rate. However, if the foaming rate is too high, the lightness is improved, but the nail pulling resistance is significantly reduced, and it is difficult to hit the crosspiece, and the bending strength is also high. Is insufficient, and it is damaged by the lateral pressure of concrete when used as a formwork. The present inventors have found that by setting the bubble generation rate to 60% or less, the nailing property and the bending strength required for the mold can be satisfied. On the other hand, in order to achieve the same lightness as compared with the wood formwork, it is necessary to make the bubble generation rate of the center layer 20% or more. As the foaming method, any of known chemical foaming, gas foaming, mechanical foaming, water foaming, and the like can be applied.

The bending rigidity of the panel is improved by arranging a highly rigid material at a position closer to the surface layer. In the present invention, the outer layer 2 is melt-kneaded with a plastic mixture having a specific gravity of 1.0 or less separated by a method such as a specific gravity separation method.
To form The plastic mixture having a specific gravity of 1.0 or less used in general waste plastics contains unavoidable impurities that cannot be separated by a specific gravity separation method. The outer layer 2 preferably has no foamed structure in order to increase rigidity. However, when the outer layer 2 has a foamed structure, the foaming ratio is set to 10% or less so that the rigidity is not impaired. In the present invention, fillers are added to the outer layer 2 in order to improve the bending rigidity of the panel. By adding fine particles having a particle size of 0.01 μm to 50 μm as fillers, rigidity and impact resistance can be improved. Since fillers have higher rigidity than waste plastic as a base resin, the addition of fillers to the outer layer is effective in improving rigidity and impact resistance. Examples of such fillers include talc, mica, silica, titania, alumina, calcium carbonate, cut glass fibers, and the like. In order to improve the rigidity, it is more effective to have a plate shape than a granular shape.

Talc is particularly effective as the fine particles used in the present invention. Since talc is a crushed product from rough stone, it is easy to obtain fine particles with a specified particle size, and it is insoluble in acids and alkalis and has excellent chemical resistance. This is because there is little effect and the effect of suppressing propagation even if a crack occurs due to being hard. The smaller the particle diameter of talc is, the better the rigidity and the impact resistance are improved, and preferably 0.01 μm to 2 μm.

The addition amount of the fine particles of the present invention is preferably 1% by mass to 40% by mass in the resin of the outer layer. If the addition amount is less than 1 mass%, there is no effect of improving the rigidity, and if it exceeds 40 mass%, it becomes brittle and the impact resistance is reduced. More preferably, the added amount of the fine particles is 5 mass% to 20 mass%.

As described above, the lightness and rigidity of the formwork panel can be satisfied, but it is difficult to obtain performance exceeding that of wood plywood. In addition, when plastic or the like, which is subject to the Containers and Packaging Recycling Law, is used as a raw material, there is a new problem that a worker has a disgust because a peculiar odor is generated when manufacturing a formwork panel.

In the present invention, the above-mentioned problem is solved by blending ground wood into the center layer 1. By containing crushed wood, the bending rigidity, bending strength, nailing property, resin entanglement of the saw blade at the time of saw cutting, and the like as a whole can be improved without substantially impairing the lightness. Furthermore, by blending the ground wood into the center layer 1, the peculiar off-flavor is extremely reduced, and the level is hardly noticeable. As the ground wood, it is preferable to use recycled materials such as construction waste materials.

The length of the above-mentioned crushed wood is as follows.
It is preferable that the length is about 0.2 to 10 mm when mixed with the water. If it is less than 0.2 mm, the effect of improving strength and rigidity is reduced, and if it is more than 10 mm, a locally weak portion is easily formed, and the strength of the panel is reduced. The mixing ratio is 3 to 50mass with respect to the entire central layer.
s% is preferred. If it is less than 3 mass%, the effect of improving strength and rigidity is reduced, and if it is more than 50 mass%, a locally weak portion is easily formed, and the strength of the panel is reduced.

Next, a method of manufacturing the plastic composite panel of the present invention will be described.

In order to form the center layer 1, a foaming agent is added to the low specific gravity component of the waste plastic, and if necessary, ground wood is added and mixed. It is charged and formed into a sheet by extrusion. Alternatively, a known molding method such as molding a mixture of a low specific gravity component, a foaming agent, and wood into a sheet shape by direct heat compression molding can be applied.

Similarly, the outer layer 2 is prepared by adding fillers to the low specific gravity component of the waste plastic and mixing the mixture, then forming the sheet into a sheet by extrusion molding, and fusion-bonding it to the center layer 1 in a heated state. Alternatively, the raw materials for the central layer and outer layer
The center layer 1 and the outer layer 2 can be formed by any method, for example, they are put into a shaft kneading extruder and integrally molded by a two-type three-layer T-die.
Are molded by melting and bonding.

[0033]

EXAMPLE According to the Containers and Packaging Recycling Law, waste plastics separated and recovered were pulverized, and then components having a specific gravity of 1.0 or less were separated by a specific gravity separation method using an aqueous solvent. The separated light specific gravity pulverized material was appropriately washed and used as a raw material. Table 1 shows an azodicarbondiamine-based blowing agent as a raw material and a chemical blowing agent.
The mixture was mixed by a mixing machine at the ratio shown in Table 1 and charged into a single-screw extruder to form a central layer. For the outer layer, 20 mass% of talc or mica was added to the raw material, and the mixture was put into a single screw extruder as in the case of the center layer.

The center layer and the outer layer were extruded into a sheet having a thickness of about 12 mm and a width of about 0.8 m while bonding them in a molten state with two types of three-layer T-die. The formed foam sheet is cooled by pressing and shaping from both sides with a belt-shaped press device, and both ends are cut, and finally 600 mm in width and 1800 in length
Panels having a thickness of 12 mm and a thickness of 12 mm were manufactured as Examples 1 to 7.

As shown in Table 2, those using PP (polypropylene) and PE (polyethylene) as the outer layer resin were produced in the same manner as Comparative Examples 1 and 2. In addition, the panel for the form of the South Sea material was used as Comparative Example 3 and was used as a criterion for evaluation of the plastic composite panel.

With respect to the plastic composite panel prepared here, the bending Young's modulus and bending strength, specific gravity, smoothness, the number of reusable times, nailing property, and odor were examined as rigidity, and performance was evaluated.

Bending Young's modulus: It was calculated by conducting a bending test in accordance with the method prescribed in Japanese Agricultural Standards “Plywood for concrete formwork”.

Bending strength: Calculated by conducting a bending test according to JIS K 7171.

Specific gravity: Calculated from the volume calculated from the dimensions of the plate and the weight.

Smoothness: Judged from the surface condition of the concrete surface when used as a formwork panel. ○ Good, △ Slight unevenness is observed, × Unevenness is remarkable Number of reusable times: When used as a concrete form as a test, until the surface layer cracks, peels off, etc., it can not be reused , The number of diversions possible.

Nail-out property: A pier of 40 × 40 mm was placed on the back of the panel, and it was hit with 100 nails from the surface, and the rate of occurrence of cracks on the panel surface was evaluated.

Odor: ほ と ん ど hardly noticed, Δ slightly disturbed, × disturbed and did not work General evaluation: Workability when used as a concrete mold on a test basis. ○ Can be used in almost the same way as wood plywood,
△ Can be used similarly with some changes such as the arrangement of crosspieces, × Cannot be used like wood plywood. These results are also shown in Tables 1 and 2.

[0043]

[Table 1]

[0044]

[Table 2]

Examples 1 to 7 of the plastic composite panel of the present invention have a bending Young's modulus of 5 GPa or more and a bending strength of 20 MPa.
As described above, the specific gravity is 0.75 or less, which is almost the same as that of the panel for the form of the South Sea, and the smoothness, nailing, and odor are the same as those of the panel for the form of the South. It is superior to the panel for the material form, and shows the same or higher performance as the wood panel in various characteristics required for the concrete form, and it is found that it can be substituted. In Comparative Example 1, the bubble formation rate of the center layer was out of the range of the present invention, and the flexural rigidity was extremely poor. Comparative Example 2 also has a high specific gravity because the bubble generation rate of the center layer is out of the range of the present invention. All of the panels of the present invention were excellent in recyclability, for example, they were blown into a blast furnace as industrial waste after use, and chemical recycling was possible instead of coke.

[0046]

As described above, the plastic composite panel for concrete formwork of the present invention satisfies the required rigidity and lightness, and is excellent in nailing, sawing and surface smoothness.
It has the ability to fully replace wood plywood. Providing such panels as raw materials of waste plastics, especially waste plastics discharged from households subject to the Containers and Packaging Recycling Law, has great industrial significance from the perspective of preventing global warming. . Further, the panel of the present invention is blown into a blast furnace after use, and can be chemically recycled as a raw material for steel, and has an effect that the total carbon dioxide reduction effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a plastic composite panel of the present invention.

[Explanation of symbols]

 1, center layer 2, outer layer 3, air bubbles

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Sachi Kitao, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Hidekazu Tsuruta 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Akihiko Furuta 1-2-1, Marunouchi, Chiyoda-ku, Tokyo F-term in Nihon Kokan Co., Ltd. (reference) 2E110 AA46 AB04 AB22 AB23 BA03 GA24W GB42W GB42Y GB42Z 4F100 AC10A AC10C AK01A AK01B AK01C AK04 AK07 AP00A AP00C BA03 BA06 BA10A BA10C BA13 DE01A DE01C DE02A DE02C DJ01B EH20 GB07 GB08 GB90 JK04 JK15 JL01 JL01A JL01B JL01C JL02 JL03 YY00A YY00B YY00C

Claims (4)

[Claims] 1. A plastic composite panel having a center layer and outer layers on both sides of the center layer, wherein the center layer and the outer layer contain a plastic mixture having a specific gravity of 1.0 or less separated from used plastic as a raw material, The center layer has a bubbling ratio of 20 to 60%, the outer layer contains fine particles having a particle diameter of 0.01 μm to 50 μm in a dispersed state, and the center layer and the outer layer are melt-bonded. Plastic composite panel. 2. The method according to claim 1, wherein the fine particles have a plate shape, and the major axis of each particle is 0.01 μm to 50 μm.
The plastic composite panel according to claim 1. 3. The plastic composite panel according to claim 1, wherein a main component of the fine particles is talc. 4. The plastic composite panel according to claim 1, further comprising crushed wood.